81397869 has 12 divisors (see below), whose sum is σ = 126249984. Its totient is φ = 46512984.

The previous prime is 81397859. The next prime is 81397871. The reversal of 81397869 is 96879318.

It is not a de Polignac number, because 81397869 - 2⁵ = 81397837 is a prime.

It is a super-2 number, since 2×81397869² = 13251226155482322, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81397829) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 276717 + ... + 277010.

It is an arithmetic number, because the mean of its divisors is an integer number (10520832).

Almost surely, 2^81397869 is an apocalyptic number.

It is an amenable number.

81397869 is a deficient number, since it is larger than the sum of its proper divisors (44852115).

81397869 is a wasteful number, since it uses less digits than its factorization.

81397869 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 553744 (or 553737 counting only the distinct ones).

The product of its digits is 653184, while the sum is 51.

The square root of 81397869 is about 9022.0767564902. The cubic root of 81397869 is about 433.3821419710.

The spelling of 81397869 in words is "eighty-one million, three hundred ninety-seven thousand, eight hundred sixty-nine".